It may; our FHEM implementation relies on external code, and as such we cannot guarantee it will not. There have been some very significant changes in the design of Raspbian since then (entirely new network stack, device overlays, sysVinit replaced with systemd, etc.).

As is the case with all production Linux systems, updating should be done cautiously and with the knowledge that things may break or require manual fixing. This is even one of the primary motivations for the version-based distribution release system, rather than automatic updates as practiced on OS X and Windows.

We will try to create an updated image at some point, but it is not a trivial thing to do.